Hereheretau Road Retreat
In January 2024, we took on a critical road stabilisation project. When a slow-moving slip threatened a key access road, our team responded by executing a major road retreat. Using a 23-tonne excavator equipped with 3D grade-assist technology, we ensured the unstable ground was removed and the new bench was cut to the millimetre—delivering the precise, permanent stability the design demanded.
Geotechnical Stabilisation: Road Retreat Saves Critical Access and Expands Capacity
The Challenge: A vital section of Hereheretau Road was under attack from two fronts: an aggressive slow-creep slip from the hillside above and constant underslip failure due to river erosion below. This combination of geotechnical hazards meant the road was perpetually unstable and required significant, ongoing maintenance. To solve the problem definitively, the Wairoa District Council required a permanent road retreat and stabilisation project.
Project Scope & Value-Add: The core of the project involved excavating a massive 6,000m³ of cut-to-waste fill to remove the unstable hill material. Beyond stabilisation, this intervention was strategically used to widen the carriageway from a single lane to a safer, more efficient double lane, complete with the installation of new riser and culvert drainage infrastructure.
The Problem with the Plan: The original methodology mandated using standard road trucks to cart the waste material along the public road under restrictive Stop/Go traffic management. This would have caused severe public disruption, dramatically escalated traffic management costs, and introduced significant safety hazards on the live road.
The Pryde Solution: Off-Road Innovation & Efficiency. We developed a superior, streamlined solution: we secured and constructed an exclusive off-road haul track across the adjacent farmland. By deploying our All-Terrain Dump Trucks, we achieved two critical goals:
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Enhanced Safety: The haul route was completely removed from the public highway, significantly reducing hazards for the general public.
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Streamlined Efficiency: The All-Terrain Trucks drove directly from the digger, eliminating the need to double-handle the excavated material—a process that accelerated the earthworks timeline.
Precision Execution & Results: A Caterpillar 323 excavator with 3D Grade Assist and a dedicated Trimble base station ensured the new cut face, bench, and batters were excavated to millimetre accuracy. The result is a stabilised, double-lane road that is safer, more efficient, and maintenance-free.
Client: Wairoa District Council (Subcontracted via QRS)